Toadstools in the compost heap

Andy M found these large toadstools - the largest being about 10cm across - sprouting out of a heap of rotting turf and compost at the bottom of his garden this weekend. These could be Agaricus bisporus - the wild relative of the commercial mushroom - but not totally sure, and definitely not sure enough to try them on toast!

Brown gills under the large cap, with two more smaller mushrooms coming up underneath